Constant Stress Creep Tester Using the Servo Divider(Metallurgy)

概要

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In order to examine the transient creep, especially its initial stage in detail, a new constant stress creep tester has been developed. The load necessary to maintain the stress constant can be obtained by an automatic control system with a servo divider, which calculates the equation, as W=W_0l_0(l_0+x), where W_0 is the initial load, l_0 is the initial gauge length and x is the elongation of the specimen. The specimen is stretched by the dead weight of water which is controlled in accordance with the calculated value. The system has the advantages of giving the load under a constant loading condition and keeping the stress constant against various disturbances. The maximum load is 100 kg with precision of ±0.3 kg, and the deviation of the load from the calculated value is within 1 kg. A new precise temperature controller which stabilizes the temperature within ±0.1℃ is also proposed. The tester makes it possible to obtain the load-elongation curves before the creep tests and creep curves up to the strain of 10%. On the basis of the fact that polycrystalline Fe-19Cr alloy exhibits the incubation phenomenon within the strain of 0.1%, it is suggested that the phenomenon will be found below such a small strain in some alloy systems which have not exhibited the phenomenon thus far.
東北大学の論文